Scientists have developed a smart contact lens that can monitor blood sugar levels from tears in the eye in patients with diabetes, spelling an end for painful needle pricks.

For diabetics, monitoring and controlling blood sugar levels are extremely important because having high blood glucose levels for extended periods of time can lead to a host of diabetes complications.

An enzyme based finger-pricking method is the most commonly used technology in diabetic assessment. However, such approach has been said to reduce compliance among diabetic patients.

The smart lens, developed by researchers from Ulsan National Institute of Science and Technology (UNIST), has built-in pliable, transparent electronics that can monitor glucose levels from tears in the eye.

Although the device has not yet been tested in humans, researchers expect it will offer diabetics a pain-free way to measure their glucose levels with the blink of an eye.In the last several decades, many attempts have been made to monitor glucose levels in tears with smart contact lenses, but they are often not used due to poor wearability.

To solve contact lens discomfort issues, the team led by Jang-Ung Park of UNIST have unveiled a new smart contact lens that uses electrodes made up of highly stretchable and transparent materials.

The clear, flexible lens also contains a glucose sensor that sends electrical signals to an LED.

With this sensor, patients can transmit their health information in real-time using the embedded wireless antenna in the lens.In the study, the research team has successfully tested their prototype lens on a live rabbit via non-invasive in-vivo testing.

The rabbit showed no signs of abnormal behaviour during repeated eye blinks and the LED pixel turned off when tear fluids with glucose concentration was over the threshold.

In addition, during the wireless operations, this smart contact lens could still maintain the eye temperature stably without abrupt heating.

"These smart contact lenses are made made of transparent nanomaterials and therefore do not obstruct the wearer's view," said Jihun Park, first author of the study published in the journal Science Advances.

"Besides, because the system uses wireless antenna to read sensor information, no separate power source, like battery is required for the smart contact lens sensors," Park said.

"Our smart contact lens provides a platform for wireless, continuous, and noninvasive monitoring of physiological conditions, as well as the detection of biomarkers associated with ocular and other diseases," said Park.

"It also offers the potential for expanded applicability in other areas, such as smart devices for drug delivery and augmented reality," he said.